Beta-keto Ester Enolate

The keto and enol forms are known as tautomers and they constantly interconvert (or tautomerize) between the two forms under acid or base catalyzed conditions. Both the reactions involve the same steps—protonation and deprotonation— although in the reverse order. The base-catalyzed reaction is initiated by the abstraction of the α hydrogen from the carbonyl compound. This abstraction forms a carbanion that is stabilized by delocalization of the negative charge across the carbonyl bond. The...

Acetoacetic ester synthesis is a method to obtain ketones from alkyl halides and β-keto esters. The reaction occurs in the presence of an alkoxide base that abstracts the acidic proton of the β-keto esters. The step results in an enolate ion which is doubly stabilized. The enolate then reacts with an alkyl halide via the SN2 process to produce an alkylated ester intermediate with a new C–C bond. The hydrolysis of the intermediate, followed by acidification, results in an alkylated β-keto acid.

Malonic ester synthesis is a method to obtain α substituted carboxylic acids from ꞵ-diesters such as diethyl malonate and alkyl halides. The reaction proceeds via abstraction of the acidic α hydrogen from a ꞵ-diester to produce a doubly stabilized enolate ion. The nucleophilic enolate attacks the alkyl halide in an SN2 manner to form an alkylated malonic ester intermediate with a new C–C bond. Further treating the intermediate with aqueous acid or base results in the hydrolysis of the two...

Triglycerides Triglycerides are triester molecules composed of a glycerol backbone that is bound to 3 fatty acids. These form the basis of many biological lipids that are found in vegetable oils and fats. Lipids that are isolated from plant material are the basis of vegetable oils, whereas lipids extracted from animals are used as lard or general sources of fats. A fatty acid molecule has a long carbon chain — between 12 and 20 carbons — with a weak organic acid at one end. Some fatty acids...

Aldehydes and ketones form enols, although only about 1% of the enol is present at the equilibrium for simple monocarbonyl compounds. The enol form is undetectable for acetaldehyde, present as only 1.5 × 10−4 % of acetone, and present as only 1.2% of cyclohexanone. Two kinds of regioisomeric enols are possible for unsymmetrical ketones, and their net composition is 1% at equilibrium. This instability is due to the lower bond energy of C=C than the C=O group. The additional instability of enols...